Transmission of data packets over wired and wireless links needs to be fast and reliable. Speed requirements are set by seemingly ever-increasing data transfer rates, and quality of service (QoS) requirements can be set by increasing system needs for accuracy in transmissions. The Qos requirements generally vary depending upon the type of data packets being transmitted. For example, voice data packets require continuous periodic transmission, and therefore, can demand a Qos that is higher, for example, than data traffic.
FIG. 1 shows an example of a wireless system that includes a base station 110 wirelessly communicating with multiple mobile units 120, 122, 124. The data packets transmitted between the base station 110 and the mobile units 120, 122, 124 can include both data and voice data packets. As a result, the QoS requirements vary between mobile units, and over time as the type of data packet for each mobile unit varies.
The overhead required to support transmission of data packets requiring a higher QoS (for example voice data packets) is typically much greater than transmission of data packets having lower QoS requirements. In some wireless systems, the base station schedules the transmission (uplink and downlink) between the base station and the mobile units. The scheduling of voice data packets can be burdensome because of the high QoS requirement of voice data packets.
The present WiMax (IEEE802.16) standard includes numerous limitations for carrying voice traffic efficiently. For example, media access protocol (MAP) overhead can be as much 50% of downlink frames for voice traffic. Methods for conveying bandwidth allocation can be inefficient, modulation and coding selections can be sub-optimal and uplink allocations can be inefficient.
It is desirable to have a system and method of efficiently communicating transmission scheduling of data packets requiring varying levels of QoS. It is additionally desirable to efficiently communicate bandwidth allocations and improve modulation and coding selections.